SHAPE AND STRUCTURE OF ALIMENTARY VISCERA OF PORPOISE. 319 



There has been much discussion as to whether this compartment should be 

 regarded as a part of the stomach, or merely a post-diaphragmatic diverticulum of 

 the oesophagus. We have already shown that it carries the gastro-splenic omentum, 

 and possesses the general peritoneal relations which one associates with the stomach, 

 and there can be no doubt that it acts simply as a triturator of the food. Moreover, 

 since the outlet is situated at right angles to the inlet, it is highly improbable that 

 food could pass from the inlet to the outlet without first of all making its way through 

 the triturator. Again, as the food which was found in the compartment was not 

 digested, there appears no reason to suppose that any digesting, takes place in this 

 chamber as the result of the regurgitation of gastric juice into it from the second 

 compartment. 



In consideration of the nature of the teeth with which the porpoise is provided— 

 viz., tearing teeth and not grinding teeth— it appears highly advantageous that the 

 stomach should be so specialised as to supply the necessary grinding or triturating 

 apparatus through the action of a chamber which is able to crumble food exactly as 

 a piece of bread might be reduced to powder by the crushing action of the hand. 

 We do not regard the similarity between its lining membrane and that of the 

 oesophagus as of itself a sufficient reason for concluding that it is a diverticulum of 

 the oesophagus, from the fact that in a one-chambered stomach the oesophageal 

 lining membrane may be prolonged for some distance upon the interior of the stomach — 

 e.g., in the pig; while from the general, but, more especially, the splenic, relations of 

 this first compartment, we are of opinion that it must be regarded as an undoubted 

 specialisation of the stomach, and not of the oesophagus. The peritoneal mesenteric 

 or omental connection between this chamber and the spleen gives a strong argument 

 for recognising the chamber as stomach, especially as the spleen always develops within 

 tbe mesentery which attaches the primitive stomach, and not the oesophagus, to the 

 dorsal wall of the abdominal cavity. That this association of the spleen with the first 

 compartment of cetacean stomachs is not peculiar to the porpoise, has been shown 

 by Sir Wm. Turner, who has recorded # a similar arrangement in the stomachs of 

 Hyperoodon rostratus, Delphinus delphis, Delphinus (Lagenorhynchus) albirostris, 

 Monodon monoceros, and Grampus griseus. We think that the term " kau-magen," 

 or masticatory stomach, would fairly express its function and its morphology. 



The second compartment, which was situated on the ventral aspect of the first, 

 and formed an acute angle with it, had very much the shape of the human stomach, 

 and presented two surfaces, two borders, and two apertures, but the chief axis lay 

 more in the long axis of the abdominal cavity than does that of the human stomach. 

 The ventral surface, rounded and convex, was in contact with the liver and the anterior 

 abdominal wall. The dorsal surface looked towards the lesser peritoneal sac, and was in 

 contact with the pancreas and chamber 1. The greater curvature measured 16 cms., 

 and had an omentum attached to it; the lesser border measured 12"5 cms. In contact 



* Turner, Jour, of Anat. and Phys., vol. xxiii. pp. 466-492, vol. xxvi. pp. 258-270. 



